Flat-Roof Drainage: Gravity vs. Syphonic Systems

Friday, December 21st, 2018 by Michael Fortenberry

Roofs need proper drainage to prevent moisture damage, and those with hardly any slope depend on it even more. It doesn’t take long before ponding water results in severe leakage. When left unaddressed for too long, the entire roof could collapse due to hydrostatic pressure. Considering that one-inch deep ponds typically weigh about 5.2 pounds per square foot, it’s imperative to have thoughtfully designed drains that inhibit significant water accumulation.

Flat-Roof Drainage: Gravity vs. Syphonic Systems

Any reliable commercial roof contractor like Fortenberry Roofing would say there are two types of drainage systems: gravity and syphonic. Let’s examine the differences between the two and determine which one is right for your property:

Gravity Drainage System

This system optimizes gravity to pull the water to the ground. Most properties use a network of gutters and downspouts hanging on the roof's edges, carrying water as it flows to the low sections.

The beauty of this configuration is that the commercial roofing system’s waterproofing membranes remain unscathed, preventing liquid before entering the building interior. The problem is that gutters and downspouts can be obtrusive, causing the aesthetics of the façade to suffer. But even when downpipes are installed out of sight, Fortenberry Roofing admits that this system also draws air in, providing less efficient drainage.

Syphonic Drainage System

Although it’s a popular alternative to the gravity drainage system, the syphonic one is similar, except it operates mechanically and organically at once. It’s equipped with a pump that sucks water at high velocity and is activated after airflow to the pipe is interrupted. This occurs when rainfall flooding the drain goes beyond the anti-vortex plate. The vacuum created by such a phenomenon instigates the natural gravitational flow of water.

When used on your commercial roofing system, the syphonic drainage technology lends more design flexibility to the building. It works without sloping pipes, reduces the chances of clogging, requires fewer outlets and downpipes, and costs less to install.

Increase your roof’s defense against ponding water, chronic leakage, and moisture damage. Call Fortenberry Roofing at 1-806-385-6761 now to discuss your roofing needs and get a no-pressure estimate in Hereford, Levelland, or Littlefield, TX.

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